QGIS/doc/userguide.html
gsherman 1f3e57c7a4 added user help documents
git-svn-id: http://svn.osgeo.org/qgis/trunk@741 c8812cc2-4d05-0410-92ff-de0c093fc19c
2004-02-07 22:06:30 +00:00

411 lines
13 KiB
HTML

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>QGIS User Guide</title>
<link type="text/css" href="skin/page.css" rel="stylesheet">
<link type="text/css" href="skin/krysalis.css" title="Krysalis" rel="alternate stylesheet">
<link href="favicon.ico" rel="shortcut icon">
</head>
<body>
<div id="toplinks">
<script src="skin/breadcrumbs.js" language="JavaScript" type="text/javascript"></script>
</div>
<form action="http://www.google.com/search" method="get">
<div id="mainheader">
<span class="textonly"> - </span><span class="textonly"> - </span><a href="http://qgis.org/" id="projectlogolink"><img alt="QGIS" src="images/project.png" id="projectlogo"></a>
</div>
</form>
<hr class="textonly">
<div class="content">
<a id="printable" href="userguide.pdf"><img alt="PDF" src="skin/images/pdfdoc.gif">PDF version</a>
<h1>QGIS User Guide</h1>
<h3>Version 0.1pre1 (Moroz)</h3>
<ul>
<li>
<a href="#Introduction">Introduction</a>
</li>
<ul></ul>
<li>
<a href="#Current+Features">Current Features</a>
</li>
<ul></ul>
<li>
<a href="#Getting+Started">Getting Started</a>
</li>
<ul>
<li>
<a href="#Installation">Installation</a>
</li>
<ul></ul>
<li>
<a href="#Starting+QGIS">Starting QGIS</a>
</li>
<ul></ul>
</ul>
<li>
<a href="#Working+with+vector+data">Working with vector data</a>
</li>
<ul>
<li>
<a href="#Loading+vector+data">Loading vector data</a>
</li>
<ul></ul>
<li>
<a href="#Changing+Symbology">Changing Symbology</a>
</li>
<ul></ul>
<li>
<a href="#Identifying+a+Feature">Identifying a Feature</a>
</li>
<ul></ul>
</ul>
<li>
<a href="#Working+with+raster+data">Working with raster data</a>
</li>
<ul>
<li>
<a href="#What+is+raster+data%3F">What is raster data?</a>
</li>
<ul></ul>
<li>
<a href="#Raster+formats+supported+in+QGIS.">Raster formats supported in QGIS.</a>
</li>
<ul></ul>
<li>
<a href="#Loading+raster+data+in+QGIS">Loading raster data in QGIS</a>
</li>
<ul></ul>
<li>
<a href="#Symbolisation+and+properties+for+raster+layers">Symbolisation and properties for raster layers</a>
</li>
<ul>
<li>
<a href="#The+general+properties+tab">The general properties tab</a>
</li>
<li>
<a href="#The+symbology+properties+tab">The symbology properties tab</a>
</li>
<li>
<a href="#The+raster+statistics+properties+tab">The raster statistics properties tab</a>
</li>
</ul>
</ul>
<li>
<a href="#Identifying+a+Feature-N101BA">Identifying a Feature</a>
</li>
<ul></ul>
</ul>
<a name="Introduction"></a>
<h2>Introduction</h2>
<p>Quantum GIS (QGIS) is designed to be a Geographic Information System (GIS)
built for Linux/Unix. QGIS currently offers basic support for vector, raster, and database formats.</p>
<a name="Current+Features"></a>
<h2>Current Features</h2>
<ul>
<li>Support for spatially enabled PostgreSQL tables using PostGIS</li>
<li>Support for ESRI shapefiles and other vector formats support by the OGR library</li>
<li>Identify features</li>
<li>Display attribute table</li>
<li>Select features</li>
<li>Persistent selections</li>
<li>Save projects</li>
<li>Support for raster formats supported by the GDAL library</li>
<li>Change vector symbology (single, graduated, and continuous)</li>
<li>Display raster data such as digital elevation models, aerial photography or
landsat imagery</li>
<li>Change raster symbology (grayscale, pseudocolor and multiband RGB)</li>
<li>Export to Mapserver map file</li>
</ul>
<a name="Getting+Started"></a>
<h2>Getting Started</h2>
<p>This section gives you a quick overview of running QGIS and examining data in
available on the QGIS web page.
</p>
<a name="Installation"></a>
<h3>Installation</h3>
<div class="section">
<p>Installation of QGIS is documented in the <a href="install.html">Installation Guide</a>.
</p>
</div>
<a name="Starting+QGIS"></a>
<h3>Starting QGIS</h3>
<div class="section">
<p>
Assuming the QGIS is installed in the PATH, you can start QGIS by typing:
<span class="codefrag">qgis</span>.</p>
<p>
When QGIS starts, an empty window is displayed as shown below.
<img alt="QGIS Main Window" src="images/qgis_mainwindow01.png">
</p>
<div class="frame note">
<div class="label">Note</div>
<div class="framecontent">Your window decorations (title bar, etc.) may appear different depending on your operating system
and window manager</div>
</div>
<p>
In addition, you can start QGIS by specifying one or more datafiles on the commandline. For example,
assuming you are in your data directory, you could start QGIS with two shapefiles and a raster file set to
load on startup:
</p>
<p>
<span class="codefrag">qgis ak_shade.tif alaska.shp majrivers.shp </span>
</p>
<p>
<img alt="QGIS Load Data On Start" src="images/qgis_load_data_on_startup.png"></p>
</div>
<a name="Working+with+vector+data"></a>
<h2>Working with vector data</h2>
<a name="Loading+vector+data"></a>
<h3>Loading vector data</h3>
<div class="section">
<p>To load one or more shapefiles, click on the Add Layer button
<img alt="Add Layer" src="images/btn_add_layer.gif">. </p>
<p>The <em>Select one or more layers to add</em> dialog box will be displayed.
<img alt="Select layers" src="images/add_layer_dialog.gif"></p>
<p>Navigate to the directory where the shapefiles reside. Select one or
more files and click ok to load them.</p>
<p>When QGIS loads a layer, it assigns a random color to it as shown
below.</p>
<p>
<img alt="Shapefiles loaded into QGIS" src="images/loaded_shapefiles.gif">
</p>
<p>
Obviously QGIS's choice of colors is not very pleasing in this case.
</p>
</div>
<a name="Changing+Symbology"></a>
<h3>Changing Symbology</h3>
<div class="section">
<p>
To make the layer more appealing, open the Layer Properties
dialog by right-clicking on a layer name
in the table of contents (left side of the QGIS window) and
selecting <em>Properties</em>.
</p>
<p>
<img alt="Layer Properties" src="images/layer_properties.gif">
</p>
<p>
If you like, change the display name of the layer by editing
the <em>Display name</em> field. Click on the <em>Symbology</em>
tab and click on the <em>Outline color</em> and <em>Fill color</em>
and select a new color from the color chooser. You can also change the
line width if desired.</p>
<p>
<img alt="Changing colors" src="images/change_symbology.gif">
</p>
<p>After making the changes, click Ok to apply the changes to
the layer. Note that the alaska layer has been renamed to Alaska and the
color has been changed to a light green:</p>
<p>
<img alt="Changing colors" src="images/changed_symbology.gif">
</p>
</div>
<a name="Identifying+a+Feature"></a>
<h3>Identifying a Feature</h3>
<div class="section"></div>
<a name="Working+with+raster+data"></a>
<h2>Working with raster data</h2>
<a name="What+is+raster+data%3F"></a>
<h3>What is raster data?</h3>
<div class="section">
<p>Raster data in GIS are matrices of discrete cells that represent features on, above or below the earth's surface. Each
cell in the raster grid is the same size, and cells are usually rectangular (in QGIS they will always be rectangular.
Typical raster datasets include 'remote sensing' data (such as aerial photography and satellite imagery) and modelled data
(such as an elevation matrix).</p>
<p>Raster data typically do not have an associated database record for each cell (unlike in vector data where it is normal
for each feature to have an associated database record).</p>
<p>In GIS, a raster layer would have geopositioning data associated with it which will allow it to be positioned
correctly in the map display to allow other vector and raster data to be overlayed with it. QGIS, can read this
geopositioning data to facilitate properly displaying map overlays.</p>
</div>
<a name="Raster+formats+supported+in+QGIS."></a>
<h3>Raster formats supported in QGIS.</h3>
<div class="section">
<p>QGIS supports a number of different raster formats. Currently tested formats include:</p>
<ul>
<li>Arc/Info Binary Grid</li>
<li>Arc/Info ASCII Grid</li>
<li>Grass Raster</li>
<li>GeoTIFF</li>
<li>Spatial Data Transfer Standard Grids (with some limitations)</li>
<li>USGS ASCII DEM</li>
<li>Erdas Imagine</li>
</ul>
<p>Because the raster implmentation in QGIS is based on the GDAL abstraction library, orther raster formats implemented
in GDAL are also likely to work, but have not yet been tested. See
<a href="http://remotesensing.org/gdal/formats_list.html">the GDAL Raster Formats page</a> for more details.</p>
</div>
<a name="Loading+raster+data+in+QGIS"></a>
<h3>Loading raster data in QGIS</h3>
<div class="section">
<p>Raster layers are loaded either by clicking on the <img alt="Load Raster" src="images/gis_add_raster_layer.png"> icon
or by selecting the View-&gt;Add Raster Layer menu option. More than one layer can be loaded at the same time
by holding down the Control key and clicking on multiple items in the file dialog.</p>
</div>
<a name="Symbolisation+and+properties+for+raster+layers"></a>
<h3>Symbolisation and properties for raster layers</h3>
<div class="section">
<p>Symbolisation of raster layers is achieved by right clicking on a raster layer legend entry and choosing 'properties':
on the popup menu that appears:</p>
<p>
<img alt="Raster Properties Popup" src="images/qgis_raster_popup_properties_selected.png">
</p>
<p>On the properties dialog for rasters you will see there are three tabs:</p>
<a name="The+general+properties+tab"></a>
<h4>The general properties tab</h4>
<p>
<img alt="Raster Properties Popup" src="images/qgis_raster_properties_general_tab.png">
</p>
<a name="The+symbology+properties+tab"></a>
<h4>The symbology properties tab</h4>
<p>
<img alt="Raster Properties Popup" src="images/qgis_raster_properties_symbology_tab.png">
</p>
<p>QGIS supports three forms of raster layer:</p>
<ul>
<li>Single Band Grayscale Rasters</li>
<li>Palette Based RGB Rasters</li>
<li>Multiband RGB Rasters</li>
</ul>
<p>From these three basic layer types, eight forms of symbolised raster display can be used:</p>
<ol>
<li>Single Band Grayscale</li>
<li>Single Band Pseudocolor</li>
<li>Paletted Grayscale (where only the red, green or blue component of the image is displayed)</li>
<li>Paletted Pseudocolor (where only the red, green or blue component of the image is displayed, but using a pseudocolor algorithm)</li>
<li>Paletted RGB</li>
<li>Multiband Grayscale (using only one of the bands to display the image)</li>
<li>Mulitiband Pseudocolor (using only one of the bands shown in pseudocolor)</li>
<li>Multiband RGB (using any combination of three bands)</li>
</ol>
<p>QGIS has the capability to invert the colours in a given layer so that light
colors become dark (and dark colors become light).</p>
<p>QGIS has the capability to invert the colours in a given layer so that light
colors become dark (and dark colors become light).</p>
<p>QGIS has the capability to invert the colours in a given layer so that light
colors become dark (and dark colors become light).</p>
<a name="The+raster+statistics+properties+tab"></a>
<h4>The raster statistics properties tab</h4>
<p>
<img alt="Raster Properties Popup" src="images/qgis_raster_properties_statistics_tab.png">
</p>
</div>
<a name="Identifying+a+Feature-N101BA"></a>
<h2>Identifying a Feature</h2>
<p>
</p>
<p>
<a href="http://sourceforge.net/"><img alt="SourceForge.net Logo" height="31" src="http://sourceforge.net/sflogo.php?group_id=55820&type=1" width="88"></a>
</p>
<div class="author">by Gary Sherman, Tim Sutton</div>
</div>
<hr class="textonly">
<div id="nav">
<div id="tabs">
<h2 id="categories">
<span class="category">Documentation</span>
</h2>
</div>
<div class="navsection">
<h3 class="navsectionheader">Documentation<span class="textonly">:</span>
</h3>
<a class="navitem" href="install.html">Installation</a><span class="textonly">-</span><span class="navitem">User Guide</span><span class="textonly">-</span>
</div>
</div>
<p class="textonly"></p>
<hr class="textonly">
<div id="footer">
<a href="skin/images/label.gif"></a><a href="skin/images/page.gif"></a><a href="skin/images/chapter.gif"></a><a href="skin/images/chapter_open.gif"></a><a href="skin/images/current.gif"></a><a href="/favicon.ico"></a><span id="copyright">Copyright &copy;
2003&nbsp;Micro Resources. All rights reserved.
</span>
<br class="textonly">
<span id="revision"><script type="text/javascript" language="JavaScript"><!--
document.write(" - "+"Last Published: " + document.lastModified);
// --></script></span>
<br class="textonly">
<span id="validation"></span>
</div>
</body>
</html>